The potential for the greatest rate of evaporational cooling occurs when temperatures are warm and the
dewpoint depression is large. As temperatures warm,
the potential to evaporate moisture in the air increases exponentially.
As dewpoint depression increases, the
relative humidity decreases and the evaporational
potential increases. Evaporative cooling potential is found by calculating the
wetbulb depression. The wetbulb depression is the difference between
the temperature and the wetbulb temperature. The wetbulb temperature is found by cooling the initial temperature
as much as possible by evaporational cooling. The largest wetbulb depressions will occur in warm and
dry air.